Implants work on days more than weight, so it depends on whether you think that's going to take 120 days or 200 days to cover that weight range.
I'm assuming closer to 120, so I'd stretch a Synovex Choice or Rev IS to 120 days when things don't break up into nice 90 day periods.  At that weight, we can stretch it some - on the back end 90 days is the most you want to go.